The concept of illusion is essential to understanding the psychological resistance to change exhibited by both ­Israelis and Palestinians.

According to Sigmund Freud, what is characteristic of illusions is that: one, they are ­derived from deep human ­wishes; and, two, the belief is held (or would be held) in the ­absence of any compelling ­evidence, or good, rational grounds, on its behalf.

It is impossible to deny that both Israelis and Palestinians are in the grip of very powerful ­illusions, which only serve to prolong the conflict and prevent any mutual understanding; in particular, the belief shared by many Israelis that they have a biblical right to the land ­(including Judea and Samaria), or among Palestinians who ­continue to insist on the right of return of the refugees, even though this has become a virtual impossibility.

It is important to note how these illusions sustain and reinforce one another, and constitute a psychological barrier, which is much more impervious to critical reflection.

The resumption of peace talks will go nowhere unless ­Israelis and Palestinians change their prejudiced perception and resistance to and fear of change, and finally come to the realisation that their fate is intertwined and neither can live in peace and security without the other.

Dr Alon Ben-Meir, professor of international relations, Centre for Global Affairs, New York University

Pressing need for more sports centres

More people are now becoming obese and I think part of the ­reason for this is that there are not enough sports centres.

There are over 90 such ­centres in Hong Kong and that may seem like a lot. However, you realise this is not the case when you try to book one.

You are unlikely to get a place unless you book very early. I accept the argument that the government should build more public housing estates because of the growing demand. However, at the same time, it should not neglect the genuine need for enough sports centres, so that people can keep fit.

Some of the most popular facilities, such as badminton courts, are always occupied and full booked. Swimming pools are frequently full.

When you are able to lead a healthy lifestyle, it can help you to relieve stress. But if they are not able to get to a sports centre, then people run a greater risk of becoming obese. I think more people would exercise if a sports centre was located close to their homes and it was easy to make a booking.

The government needs to look into this matter and address the problem promptly. This is an important health issue and must be addressed.

Michelle Chu Wing-shan, Yau Yat Chuen

Children must always have a balanced diet

I am concerned about childhood obesity, which is becoming a growing problem in Hong Kong.

I think action needs to be taken to deal with this problem, which affects young people of all ages before it gets out of control.

I believe there are different reasons that account for this problem. A lot of children concentrate on their studies and do not get enough exercise. Of course, their studies are important, but they must not neglect the importance of exercise. They also need to be aware of their diets. Too often, they eat too much fast food, which contains too much oil and salt.

In some cases, of course, there are genetic factors at play.

Obesity can bring a lot of ­serious health problems during childhood and in later life, such as high blood pressure and diabetes.

It can also lead to young people having negative feelings about themselves and this can be bad for their physical and mental development.

Schools should address this problem and organise more physical education ­lessons on the school syllabus.

Having more PE lessons ­enables children to get more exercise, which helps them burn off fat.

Moreover, parents can lead by example and use less oil and salt when they cook, or cook more vegetables.

They should cut back on the number of snacks their children are allowed to eat and the aim should always be for a balanced diet.

Winnie Lei Yuen-lam, Sham Shui Po

Climate change deal is at least a good start

I think the deal reached at the UN climate change summit in Paris earlier this month was a good beginning.

As a geography student, I can appreciate the severity of ­climate change. The average temperature globally has been increasing. This has a number of negative side-effects, including rising sea levels, more frequent episodes of extreme weather and changes to ecosystems, such as the bleaching of corals.

These changes can have many adverse social and economic side-effects for people. For example, with rising sea levels, there will be more ­flooding of coastal areas and more storm surges. Some low-lying nations could be submerged. Also, global warming will affect agriculture and supplies of food and fresh water.

With warmer weather, there will be more pests and more destruction of crops.

This could lead to a decline in food production in some places. As a consequence, millions more people will face famine and hunger.

I think the agreement to restrict warming of the planet to about 2 degrees ­Celsius is a good start and can help to reduce the impact of ­climate change. It is important that developed and developing nations play their part and try to reduce levels of pollution, as this earth belongs to us all.

We can all play our part and be more environmentally friendly.

Yoyo Sin Lok-yiu, Cheung Sha Wan

So many in the world are suffering

There are so many social problems in the world today.

Every day you read news ­reports about people who are in need, including the large ­numbers of refugees coming into Europe. Too many of us ­appear to be blind to these problems. We just focus on our own lives.

These refugees have had to leave the countries where they were born and brought up and are in desperate need of a home.

I think the government can do more in the area of education to make people more aware of the problems so many face.

It could have an advertising campaign so that people are more aware of the benefits from helping others.

Schools should also try and get this message across in ­lessons. They could organise fund-raising and other activities such as having students visit elderly citizens.

Parents can also offer some guidance to their children. Many youngsters grow up in a privileged environment in Hong Kong and this is an affluent city. They may not appreciate the problems people experience who are living in poverty.

They need to become more aware of the poor.

We all need to cooperate so that we can help those who are suffering in society.

Rita Chan Man-ting, To Kwa Wan

Some criticism of TSA test has been unfair

Some parents of primary school pupils called for a class boycott, because they want to see the Territory-wide System Assessment (TSA) test for their children scrapped.

There has been extensive discussion of the TSA and ­parents argue that the problem is getting out of control. There is no doubt that if it is causing ­distress to children, then feasible solutions must be found to alleviate that distress. But, I disagree with those people who want to see the TSA cancelled for ­primary pupils in local schools.

Parents are being unfair when they blame the TSA for all the pressure placed on students. Stress can come from various sources.

It can come from other ­family members, peers and the school itself. For example, often, parents have unrealistically high expectations of their children.

Some children may feel ­upset if they are in a school where they have no friends or few friends.

If the TSA does put children under a degree of ­pressure, then they need to learn to deal with it. Once they are grown up and in the adult world, they will have to face a lot of pressure and they need to get used to that and prepare for it.

If there are problems with the TSA and it is too difficult, then the government needs to figure out how to improve that situation.

Alison Yu Tsz-man, Sham Shui Po